Nitric Oxide Inhibits Exocytosis

Researchers have found that nitric oxide reduces blood vessel inflammation by blocking the process of exocytosis whereby molecules that stimulate an inflammatory response are released into the blood stream.

Investigators at Johns Hopkins University (Baltimore, MD, USA; www.jhu.edu) used both human cells growing in tissue culture and a mouse model to investigate the effect of nitric oxide on inflammation. They reported in the October 17, 2003, issue of Cell that nitric oxide inhibited exocytosis of Weibel-Palade bodies, endothelial granules that mediate vascular inflammation and thrombosis, by regulating the activity of N-ethylmaleimide-sensitive factor (NSF). Nitric oxide inhibited NSF disassembly of soluble NSF attachment protein receptor (SNARE) complexes by nitrosylating critical cysteine residues of NSF.

"Nitric oxide may regulate exocytosis this way in a variety of diseases,” explained senior author Dr. Charles J. Lowenstein, associate professor of medicine at Johns Hopkins University. "For example, nitric oxide blocks exocytosis from platelets, preventing blood clots; exocytosis from neurons, decreasing neurotoxicity in strokes; and exocystosis from lymphocytes, reducing autoimmune damage.”




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